In vehicles that use an electric drive/traction motor as a propulsion source, such as electric vehicles and hybrid vehicles, the motor is driven so that the output torque of the motor matches a torque instruction from a vehicle control device. The torque instruction from the vehicle control device may be an instructed torque value to be output by the motor.
The power conversion device for driving a motor in such a vehicle is generally accompanied by a control device, which generates a control signal for driving the motor with the instructed torque based on an electric current flowing in the motor and a rotation angle representing a rotation position of a rotor in the motor.
The control device uses two systems, a control system for driving the motor via the power conversion device, and a monitoring system for monitoring the output torque of the motor and performing abnormality determination, where the control and monitoring systems are provided as two separate microcomputers.
The control system and the monitoring system provided as separate microcomputers may complicate the configuration of the control device and increase the manufacturing costs.
However, when both of the control system and the monitoring system in the control device described above are implemented by one microcomputer, hardware resources such as the current detection unit and the angle detection unit in one microcomputer are shared, e.g., used in a time-sharing manner, by the control system and the monitoring system, for the detection and acquisition of the current and the angle.
The hardware resources used in a sharing manner by the control system and the monitoring system for the acquiring the current and the angle may cause a “collision,” where the acquisition request for the current from the control system and the acquisition request for the angle from the monitoring system occur almost simultaneously and collide. Collisions may affect the synchronism between the current acquisition and the angle acquisition, where the current and the angle are detected at different detection times.
Accordingly, control devices of power conversion devices of motors are subject to improvement.